The present invention relates to a device for removing one or more undesirable substances or dangerous substances for humans from a gas or a vapor mixture, a gas mask filter, comprising such a device, a gas mask comprising such a filter and a method for warning of the presence of undesirable or dangerous substances.
Filters are used in order to remove dangerous substances from the air. Gas masks provided with filters are for example used for removing many sorts of poisonous components from air to be breathed.
In certain professions it is advisable to wear a gas mask. Furthermore, national laws increasingly require that the gas masks be worn for example in the building profession by painters and fitters who in their daily work in enclosed areas run a relatively large risk of coming into contact with dangerous chemicals. Gas masks are also worn in war situations.
The removal of undesirable or dangerous substances in vapor or gas form is presently, usually carried out in a gas mask filter by means of adsorption of these substances onto a layer of activated carbon. The more dangerous substances are adsorbed, the more the layer of activated carbon is saturated whereby the adsorption capacity of the filter decreases in time. The capacity of a filter is difficult to predict. The rate at which such filters are used up is an uncertain factor, since this is dependent on parameters such as the environmental temperature, the nature and concentration of the contaminants to be adsorbed and the rate and amount of breathing of the gas mask user. In practice the filters are seldom changed at the correct moment, i.e. the moment in time whereby adsorption in (substantially) no longer possible and as a consequence whereby dangerous substances begin to reach the user. When filters are changed too early, this leads to an unnecessary high usage thereof with the accompanying economic disadvantages, whilst changing a filter too late means that the user runs the risk of damage to the health.
It is an object of the present invention to substantially obviate one or more disadvantages of the state of the art, such as the above mentioned disadvantages, and/or to provide an improved use of a gas mask especially by providing an alarm with respect to the saturation level of the filter of a gas mask.